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Petersen" , "daniel@iogearbox.net" , Christoph Hellwig , Dan Williams , "jack@suse.com" , Leon Romanovsky Subject: Re: [LSF/MM/BPF TOPIC] [LSF/MM/BPF ATTEND] : Two stage IOMMU DMA mapping operations Message-ID: <20240305130331.GA3662014@nvidia.com> References: <97f385db-42c9-4c04-8fba-9b1ba8ffc525@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <97f385db-42c9-4c04-8fba-9b1ba8ffc525@nvidia.com> X-ClientProxiedBy: MN2PR16CA0045.namprd16.prod.outlook.com (2603:10b6:208:234::14) To DM6PR12MB3849.namprd12.prod.outlook.com (2603:10b6:5:1c7::26) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6PR12MB3849:EE_|IA1PR12MB6283:EE_ X-MS-Office365-Filtering-Correlation-Id: 761a7a9f-e14a-430f-dd32-08dc3d14a901 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM6PR12MB3849.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(376005);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?0Z58lEAKeFXJ73KUifURIaSg/7c6NRl1e+75Mao/7tdTsws6Dy6t+2yIVfVd?= =?us-ascii?Q?T5E+qNRJc5hLmnP9FswKiXckU60qTIrLaIn9QmCGfxIP2VjDay3IDjr7e/AA?= =?us-ascii?Q?tk7H9OobtK1oyEk8Ks5BD/IfOUXRpfeH4GYnlbaEXuf3CtguVz2P93qFDFP3?= =?us-ascii?Q?hw9PD3HI9/tYfhuLjRrhQStHlJCaM4efAmAYtTeofpyN3Od2mNGn6m6N/Fmv?= =?us-ascii?Q?SWUQTD9o1fztYypEYcglMRpkn8F0wu18Pvu2m92qMoCwuNTl8lKLbrFD94DW?= =?us-ascii?Q?D7kCuOwyaJ2/hFMmXuiTas4IgDyiBgHPMdzuylU5QK2jBEnlWe2loBE8GPNh?= =?us-ascii?Q?YF0jBli71/SNCGX6OhGph3mULTSHlfBSL3v0S7ZRjoc37WQiJpf45hXQF1Ag?= =?us-ascii?Q?K60rwCZTBiHuSvZJOcXp7R7OMNIUpsGaXDcWYkBiSIsuq2BcIBDftdPxLYP0?= =?us-ascii?Q?6IXmigZAZeFb6VNuhX+CIAVvQBIE93MzOU5E2p7xwGPSZFao2GArRDASAR4Y?= =?us-ascii?Q?b8X245pn+eVyW3nypmy/sgSUktJWZk9bdsQq67uZbubuM1oTMZhrK82O128B?= =?us-ascii?Q?vtbEncGos3HpQZNUDpN94Pzu14u9cz9pDrr45RAG8+UTgcx1tdLbgcYyOuTe?= =?us-ascii?Q?9/TmB0/gd5hd1c5ATYyLzFrobpXG//s/Rdml+GKQsiE4lJMdO+/q63NhSqzV?= =?us-ascii?Q?LKb+qQm61K92TL/mMLE51nfBjEMM5fkeNRSpD9TKeeRT8BdoeEJtAgVYVUPj?= =?us-ascii?Q?MG3nWSm8sl51Skzvqta/RucmVGzdEsWJZgxqhjQwx1g5AbTrFNzXK5srnWKo?= =?us-ascii?Q?A10OVUZ/OM36JiHsKKfhIOTLgVuxl9bF74cFeh290tayKdddQFPPsoWFyr6P?= =?us-ascii?Q?5kwysK3Y5HMWU9H+JgYSFWSgAFtuW5euddln/TOPiUaxzUGSnsjPvZd9evCO?= =?us-ascii?Q?nLk5SZOIO2Xw5nXXWTZ8tmtaVUQcMnAC0GOQIc9DUPxjMKRNHLWdaExwTM/r?= =?us-ascii?Q?dUGQGeTPtDlipaJ7H7VdH7fac079qGjlGtiPPNvajN4gFkDjwPmZNcKYydJX?= =?us-ascii?Q?o/rbSDq7jOMs0qnwSGqvcdeH+bNb/sm9Umpb6NhNI/WH7qg3HxxgUS3qwUUR?= =?us-ascii?Q?tzyvMZt5R2FTPhNHqDhDrEYJ+7purM8yjJM0IShwlf0p5NVdLWsiMAWthpAA?= =?us-ascii?Q?z3pFdvCEkUCC35q6w2nrBrD/oLP8c4+cb+BKA3SVMM61xv9K8wFlh1gYqZ4t?= =?us-ascii?Q?iNjjCdVRhxqH/5YOjl1LGZ+nRmEB7NIgErCrKBecAWXNws7Rqi+3xE8cO7AA?= =?us-ascii?Q?Mt/yGEcwXhUYC3y4S8Oc9vUNBboxUSLuDO8pszij4ZQh6Nc4uaiuo4g5nvuJ?= =?us-ascii?Q?LR+8V68WWB8RuaobVaDyszN86ZNPnKOwh/e5ZULrLew/+dQr8oQeX/3rK6J2?= =?us-ascii?Q?Uue6yGc6R9WutOBfKJWxMFxbFdtYlS5GRFiU2CyZuHUQ2p+ON+b6H3+TUpWd?= =?us-ascii?Q?rRMTPq9BITEAhN9bvosYi/Ji33A9MMsb8cpbpBQa8mSfmLFZfwK4MiYRLAtQ?= =?us-ascii?Q?lTWb2vfdYhSVeAGC/eiJvf7Ub7nwgcYAy7QK56ns?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 761a7a9f-e14a-430f-dd32-08dc3d14a901 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3849.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Mar 2024 13:03:32.5512 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: VuZW6Q7xbI32S1XWEWBwJlxiAg8MB31KwiFpkVb9euxpo9tu/9FZWtbom0UPcURi X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6283 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240305_050347_508242_A2757CF2 X-CRM114-Status: GOOD ( 10.00 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Feb 27, 2024 at 08:17:27AM +0000, Chaitanya Kulkarni wrote: > Hi, > > * Problem Statement :- > ------------------------------------------------------------------------- > The existing IOMMU DMA mapping operation is performed in two steps at the > same time (one-shot): > 1. Allocates IOVA space. > 2. Actually maps DMA pages to that space. > For example, map scatter-gather list: For clarity, this has come out of last years topic on the "physr" - we agreed to a general direction where instead of adding a parallel DMA API surface for a new scatterlist alternative we'd improve the DMA API so callers can efficiently bring their own data structure. https://lore.kernel.org/linux-rdma/Y8v+qVZ8OmodOCQ9@nvidia.com/ Jason